Property variations in large AlSi7 alloy foam ingots

The actual foam density affects its mechanical energy absorption capabilities. Making structural elements starting from the cutting of semi-finished items may produce uneven results due to the lack of homogeneity in the foam. The subject of this work is the study of AlSi7 metallic foams, the focus being on the evaluation of the effective density distribution throughout large ingots. This is the first step required to establish a correlation between manufacturing process parameters and mechanical properties. The results highlighted that the void density increases from the centre toward the ingot outer wall and that specimens coming from different regions of the ingot have a very different mechanical behaviour. This is probably due to the difficulty in controlling temperature gradients and cooling rates throughout big mould cavities during the production process.